Welding operation liquid crystal protection mask

ABSTRACT

A welding-operation, liquid crystal, protection mask for protecting the eyes of a human operator from an arc light generated during a welding operation, comprises a liquid crystal protection mask main body adapted to be attached to the face of a human operator; a detecting means disposed in the vicinity of the liquid crystal protection mask main body and capable of detecting an incident arc light generated during the welding operation and thus producing a detection result; a liquid crystal light blocking section that is disposed in a position corresponding to the eyes of a human operator wearing the protection mask with the human face being covered by the protection mask main body and that has a liquid crystal member that is capable of blocking the incident light by instantaneously reducing the light transmittance of the liquid crystal in accordance with the detection result output from the detecting means and by means of a liquid crystal driving power source; and a polarizing plate that is provided in front of the detecting means to cover up the detecting means and that is capable of controlling the orientation of the incident light.

[0001] The present invention relates to a welding-operation, liquidcrystal, protection mask that has a light blocking device for protectingthe eyes of a human operator from an arc light generated during awelding operation. In more detail, the present invention relates to awelding-operation, liquid crystal, protection mask that is simple instructure but excellent in its detection precision when detecting an arclight, so that the light blocking device will actuate only when a humanoperator who wears the liquid crystal protection mask has their arclight on. The invention thus prevents a welding mask from improperlyoperating when it detects light(s) other than the arc light of theoperator, thereby improving operator's safety during a weldingoperation.

BACKGROUND

[0002] In the past, a light protection mask has used a light blockingplate to protect a human operator's eyes from an arc light that isgenerated during a welding operation. More recently, awelding-operation, liquid crystal, protection mask has been developed,which mask is equipped with a liquid crystal plate that is capable ofblocking a light by instantaneously reducing the light transmittance ofa liquid crystal. These known welding-operation, liquid crystal,protection masks, however, have been found to have some drawbacks. Whenmany human operators are conducting welding operations at the same time,the light transmittance of the light blocking plate being used by onehuman operator may be undesirably actuated by nearby arc lights of otherwelders and also by illumination lights.

[0003] Because known welding-operation, liquid crystal, protection masksare designed for the purpose of sufficiently protecting the eyes of ahuman operator, they are usually constructed so that light transmittanceduring a light blocking operation is extremely small. As a result, ahuman operator typically can recognize nothing but a welding point whenthe device is activated. For this reason, when a mistaken light blockingoperation occurs that is out of control of a human operator during thewelding operation, the operator will suddenly become unable to see,creating an extremely dangerous condition for them.

[0004] In order to prevent this situation from occurring, it has beensuggested that a light blocking cylindrical member be used in front of alight receiving member, which cylindrical member consists of anultraviolet light detecting element, so as to form an improvedwelding-operation, liquid crystal, protection mask that only responds toincident light that arrives from the front (see Japanese UnexaminedPatent Application Publication No. 2-159272). This knownwelding-operation, liquid crystal, protection mask is beneficial in thatit can treat an arc light entering at an incidence angle of a certainnarrow range from a position ahead of the light receiving member.

[0005] The arc light detector, however, not only responds to an arclight entering at an incidence angle of a narrow range from a positionahead of the light receiving member, but also responds to other lightsthat reach the light receiving member from other directions, includingarc lights generated and reflected during the welding operations ofother human operators. As a result, the cylindrical light blockingmember used in the above-discussed liquid crystal protection mask failsto effectively avoid a problem of detecting other lights. Thus, it hasbeen proved difficult to obtain a desired and satisfactory detectionprecision.

SUMMARY OF THE INVENTION

[0006] The present invention is provided to overcome the above problemsby furnishing the art with an improved welding-operation, liquidcrystal, protection mask that has a light blocking device for protectingthe eyes of a human operator from an arc light generated during awelding operation. Specifically, the present invention provides awelding-operation, liquid crystal, protection mask that is simple instructure but excellent in its detection precision when detecting an arclight, so that the light blocking device will actuate only when theliquid crystal protection mask has detected an arc light of that userduring their welding operation, thus preventing a mistaken lightblocking operation, which is possibly caused by the light blockingdevice when it has detected a non-arc light. The invention thus has thebenefit of improving the safety of the human operator during a weldingoperation.

[0007] According to the present invention, there is provided awelding-operation, liquid crystal, protection mask for protecting theeyes of a human operator from an arc light generated during a weldingoperation, which comprises a liquid crystal protection mask main bodythat is adapted to be attached to the face of a human operator; adetecting means disposed in the vicinity of the liquid crystalprotection mask main body and capable of detecting an incident arc lightgenerated during the welding operation and thus producing a detectionresult; a liquid crystal light blocking section that is disposed in aposition corresponding to the eyes of a human operator wearing theprotection mask with the human face being covered by the protection maskmain body, and which has a liquid crystal member capable of blocking theincident light by instantaneously reducing the light transmittance ofthe liquid crystal in accordance with the detection result output fromthe detecting means and by means of a liquid crystal driving powersource; and a polarizing member that is provided in front of thedetecting means to cover up the detecting means, and which is capable ofcontrolling the orientation of the incident light.

[0008] The welding-operation, liquid crystal, protection mask mayfurther comprise a cover plate that is disposed so as to cover up atleast the front surface of the liquid crystal light blocking section, toprotect the liquid crystal member from welding sputters and a mechanicalstress during the welding operation.

[0009] In the welding-operation, liquid crystal, protection mask, thepolarizing member may be a polarizing film that is formed by two piecesof plastic films that have a louver device interposed therebetween.

[0010] In the welding-operation, liquid crystal, protection mask, thepolarizing member may be constructed that when lights are incident onthe polarizing member, only the lights having incidence angles of 24degrees or smaller (right and left with respect to the rectilinearlypropagating light) are allowed to pass through the polarizing member,thereby effecting the control of the orientation of the incident arclight. The detecting means may also include an open-ended cylindricalmember disposed in a predetermined position adjacent to the liquidcrystal light blocking section, and a light receiving member disposed onthe bottom of the open-ended cylindrical member for receiving anincident light.

[0011] The liquid crystal member may be a liquid crystal plate, theliquid crystal driving power source may be a solar battery, and thecover plate may be a transparent protection plate.

[0012] The present invention can provide a welding-operation, liquidcrystal, protection mask that is simple in structure but excellent inits detecting precision when detecting an arc light, so that the lightblocking device will actuate only when a human operator wearing theliquid crystal protection mask has detected an arc light during his orher welding operation, thus preventing a mistaken light blockingoperation which is often caused by the light blocking device when it hasdetected a non-arc light, thereby ensuring an improved safety for thehuman operator in his or her welding operation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a perspective view that schematically shows anembodiment of a welding-operation, liquid crystal, protection maskaccording to the present invention.

[0014]FIG. 2 is a perspective view that schematically shows a detectingmeans used in the embodiment of the welding-operation, liquid crystal,protection mask according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0015] As shown in FIG. 1, a welding-operation, liquid crystal,protection mask of the present invention is a protection mask forprotecting the eyes of a human operator from an arc light generatedduring his or her welding operation. Specifically, thewelding-operation, liquid crystal, protection mask is characterized inthat it comprises a liquid crystal protection mask main body 1 that isadapted to be attached to the face of a human operator; a detectingmeans 2 disposed in the vicinity of the liquid crystal protection maskmain body 1 and capable of detecting an incident arc light generatedduring the welding operation and thus producing a detection result; aliquid crystal light blocking section 3 that is disposed in a positioncorresponding to the eyes of a human operator wearing the protectionmask with his or her face being covered by the protection mask main body1 and that has a liquid crystal member that is capable of blocking theincident light by instantaneously reducing the light transmittance ofthe liquid crystal in accordance with the detection result output fromthe detecting means 2; a cover plate 4 that (if used) is disposed infront of the liquid crystal light blocking section 3 so as to protectthe liquid crystal member and the like from sputters during the weldingoperation. The welding-operation, liquid crystal, protection mask mayfurther have a polarizing member 5 that is capable of controlling theorientation of the incident light and that is provided in front of thedetecting means 2 so as to cover up the detecting means.

[0016] Each of the above elements forming the welding-operation, liquidcrystal, protection mask are further described in detail below.

[0017] 1. Liquid Crystal Protection Mask Main Body

[0018] In order to protect a human operator from harmful weldingsputters and to protect the eyes of the human operator from an arc lightby means of the liquid crystal blocking section (that will be describedlater), the liquid crystal protection mask main body of the presentinvention is preferred to be made from a specific material and ispreferred to have a specific shape such that it can be easily fit on theface of a human operator and can enable the human operator to clearlyrecognize a welding position after they have donned the protection mask.For example, the protection mask main body may be made from either ametal such as a steel or a plastic material such as a polycarbonate,which has an excellent flame resistance, heat resistance, and abrasionresistance, and should have an appropriate shape suitable for coveringthe entire face of a human operator after the human operator has put iton.

[0019] The detailed structure of the liquid crystal protection mask mainbody is shown in FIG. 1. As illustrated in the drawing, the protectionmask main body includes a human face contact portion 11 and an engagingsection 12, the latter of which is adapted to receive a liquid crystalunit 7 that contains the detecting means 2, the liquid crystal lightblocking section 3, and a liquid crystal driving power source 6.

[0020] The liquid crystal protection mask main body may also beattached, for example, to a helmet or a band, so that it can be fixed onthe head of a human operator when it is being used.

[0021] 2. Liquid Crystal Light Blocking Section

[0022] The liquid crystal light blocking section of the presentinvention may be disposed in a position corresponding to the eyes of ahuman operator who wears the protection mask with their face beingcovered by the protection mask main body, so as to effectively block anarc light generated during the welding operation.

[0023] The liquid crystal light blocking section of the presentinvention may have a liquid crystal member that is capable of detecting,by virtue of the detecting means (which will be described in more detailbelow), an arc light generated during the welding operation, and theninstantaneously reducing the light transmittance of the liquid crystalby means of a liquid crystal driving power source, thereby blocking anincident arc light.

[0024] For use as such a liquid crystal member, it is preferred to useone that is capable of changing the light transmittance thereofcontinuously or in a plurality of steps, in accordance with themagnitude of a voltage being applied thereon.

[0025] As a preferred example for use as the liquid crystal member, itis allowed to give out the following liquid crystal plate.

[0026] For example, it is possible to use a liquid crystal plate that isformed by laminating together two liquid crystal films, capable ofchanging the light transmittance of an entire liquid crystal in aplurality of steps by changing the light transmittance of the individualliquid crystal films. Alternatively, a variable resistor is connectedbetween the detecting means and the liquid crystal light blockingsection so as to adjust an applied voltage.

[0027] As shown in FIG. 1, the liquid crystal light blocking section 3,the detecting means 2 and the liquid crystal driving power source 6, arearranged in a manner such that a liquid crystal unit 7 is integrallyformed from these elements. The liquid crystal unit 7 is then engagedinto the engaging section 12 formed on the main body 1 of the liquidcrystal protection mask.

[0028] For use as the liquid crystal driving power source, it ispreferred to use a solar battery that is small in thickness and light inweight, and is capable of converting lights in the surroundingenvironment and an arc light generated during a welding operation intoan electric energy.

[0029] In addition, such a liquid crystal driving power source can alsobe used to drive the detecting means, as will be described in thefollowing.

[0030] 3. Detecting Means

[0031] As shown in FIG. 1, the detecting means 2 of the presentinvention may be disposed in a predetermined position adjacent to boththe liquid crystal protection mask main body 1 and the liquid crystallight blocking section 3, so as to detect the incident arc lightgenerated during the welding operation and to produce a detection resultto the liquid crystal light blocking section 3.

[0032] As a preferred example of the detecting means, FIG. 2 shows acylindrical member 8 that has both ends thereof opened and disposed in apredetermined position adjacent to the liquid crystal light blockingsection 3. FIG. 2 also includes a light receiving member 9 disposed onthe bottom of the open-ended cylindrical member 8 for receiving anincident light.

[0033] As the open-ended cylindrical member, it is allowed to use astructure either having an elliptical cross section with its longer axisbeing about 5 mm and its shorter axis being about 3 mm, or having acircular cross section with its diameter being about 4 mm. In bothcases, the open-ended cylindrical member has a depth of about 7 mm.

[0034] As the light receiving member that is disposed on the bottom ofthe open-ended cylindrical member, it is allowed to use a structure thathas a detecting means capable of detecting an ultraviolet light, avisible light, and an infrared light, and which is so constructed that asignal will be input into the liquid crystal light blocking section whena predetermined amount of light has been incident on the detectingmeans.

[0035] 4. Cover Plate

[0036] The cover plate which (if used) is disposed in a manner such thatit can cover up at least the front face of the liquid crystal lightblocking section, so as to protect the liquid crystal light blockingsection from welding sputter and other mechanical stress.

[0037] As shown in FIG. 1, the cover plate 4 is disposed so as to coverthe entire face of the liquid crystal unit 7 (including the detectingmeans 2, the liquid crystal light blocking section 3, and the liquidcrystal driving power source (solar battery 6)).

[0038] There is not any specific restriction to the cover plate,provided that it has a desired light transmittancy. For example, thecover plate may take the form of an inorganic plate such as a glassplate and a ceramic plate, or a plastic plate such as a polycarbonateplate and an acryl plate each having an excellent flame resistance, heatresistance and abrasion resistance.

[0039] The cover plate, for example, may be engaged into a cover plateengaging section (not shown) provided on the liquid crystal unit.

[0040] 5. Polarizing Member

[0041] As shown in FIG. 1, the polarizing member 5 that can be used inthe present invention is shown in front of the detecting means 2 so asto cover the detecting means 2, thereby controlling the orientation ofan incident light incident on the detecting means 2.

[0042] There is not any limitation to such a polarizing member, providedthat it can effectively control the orientation of the incident light.For example, it is preferred to use a polarizing film formed by twopieces of plastic films with a louver device clamped therebetween.

[0043] In more detail, the polarizing member may be a plastic film thatis equipped with a louver, as disclosed in Japanese Examined PatentApplication Publication No. 8-11211 and Japanese Unexamined UtilityModel Application Publication No. 2-117585. Also, it is possible to useother types of polarizing films such as those that are commerciallyavailable under trade names “COMPUTER FILTER PF13B” and “LIGHT CONTROLFILM” and produced by SUMITOMO 3M CO., LTD.

[0044] Further, if it is desired to achieve a better detectionprecision, it is preferred to use a polarizing member that is soconstructed such that when lights are incident on the polarizing member,only the lights having incidence angles of 24 degrees or smaller (rightand left with respect to the rectilinearly propagating light) areallowed to pass through the polarizing member, thereby effecting thedesired control of the orientation of an incident arc light.

[0045] The polarizing member may be attached to the mask main body usingan adhesive agent, in a manner such that it can cover the upper surfaceof the detecting means. Alternatively, the polarizing member may beengaged in the cover plate engaging section in which the cover plate isengaged.

[0046] Since the polarizing member is light in weight and does notinclude any protruding portions, it will not hamper a welding operationthat is performed by a human operator who wears a protection mask thatcontains such a polarizing member. In addition, since the use of thepolarizing member can provide good detection precision, it is sure for ahuman operator to perform the welding operation smoothly and with anincreased safety.

EXAMPLE

[0047] In the following, the present invention will be described in moredetail with reference to an example. However, this invention should notbe limited to the product so described.

Example 1

[0048] A cover plate installed in a liquid crystal type protection mask(commercially available under a trade name “R-SERIESE DM9 LIQUID CRYSTALTYPE” and produced by Minnesota Mining and Manufacturing Company (3 M),U.S. A) was removed from the cover plate engaging section. Then, apolarizing film (commercially available under a trade name “COMPUTERFILTER PF13B” and produced by SUMITOMO 3M CO., LTD.) was engaged intothe liquid crystal unit engaging section to cover the front face of thelight receiving member of the detecting means. In detail, the polarizingfilm was in a rectangular shape having a length of 107 mm and a width of7 mm, and was attached with its longitudinal direction beingperpendicular to the arrangement direction of a micro louver.Subsequently, the cover plate was again attached to the liquid crystalunit engaging section and was fixed thereon.

Comparative Example 1

[0049] The Comparative Example was carried out in the same manner as theabove Example 1, except that the polarizing film was not used.

[0050] Evaluation on Detection Precision

[0051] Lamps (commercially available under a trade name “PHOTO REFLECTORLAMP DAYLIGHT COLOR 100 V, 350 W” and produced by LAMP TOSHIBA CO.,LTD.) were placed at a distance of 55 cm right above thewelding-operation, liquid crystal, protection masks obtained in Example1 and Comparative Example 1. Then, the lamps were gradually moved awayfrom the above positions while continuously maintaining the abovedistance. In this way, the incidence angles of the lights from the lampswhen they are incident on the detecting means (light receiving members)of the liquid crystal protection masks were changed gradually. At thesame time, various incidence angles detected by the detecting means wererecorded so that the detection precisions were evaluated.

[0052] As a result, it was found that when the protection mask obtainedin Example 1 was used, the detecting means could no longer continue itsdetecting function once the incidence angle became larger than 24degrees on each side (48 degrees in all) with respect to a rectilinearlypropagating light coming from an overhead position right above it. Onthe other hand, when the protection mask obtained in Comparative Example1 was used, the detecting means could continue its detecting functionuntil the incidence angle became 35 degrees on each side (70 degrees inall) with respect to a rectilinearly propagating light coming from anoverhead position right above it.

1. A welding-operation, liquid crystal, protection mask for protectingthe eyes of a human operator from an arc light generated during awelding operation, which mask comprises: a liquid crystal protectionmask main body that is adapted to be attached to the face of a humanoperator; a detecting means that is disposed in the vicinity of theliquid crystal protection mask main body and that is capable ofdetecting an incident arc light generated during the welding operationand thus producing a detection result; a liquid crystal light blockingsection that is disposed in a position corresponding to the eyes of ahuman operator wearing the protection mask with the human face beingcovered by the protection mask main body and that has a liquid crystalmember that is capable of blocking the incident light by instantaneouslyreducing the light transmittance of the liquid crystal in accordancewith the detection result output from the detecting means and by meansof a liquid crystal driving power source; and a polarizing member thatis provided in front of the detecting means to cover up the detectingmeans and that is capable of controlling the orientation of the incidentlight.
 2. The welding-operation, liquid crystal, protection of claim 1,further comprising: a cover plate that is disposed so as to cover up atleast the front surface of the liquid crystal light blocking section,thereby protecting the liquid crystal member from sputters andmechanical stress during the welding operation.
 3. Thewelding-operation, liquid crystal, protection mask of claim 1, whereinthe polarizing member is a polarizing film formed by two pieces ofplastic films with a louver device interposed therebetween.
 4. Thewelding-operation, liquid crystal, protection mask of claim 1, whereinthe polarizing member is so constructed that when lights are incident onthe polarizing member, only the lights having incidence angles of 24degrees or smaller (right and left with respect to the rectilinearlypropagating light) are allowed to pass through the polarizing member,thereby effecting the control of the orientation of the incident arclight.
 5. The welding-operation, liquid crystal, protection mask ofclaim 1, wherein the detecting means includes an open-ended cylindricalmember disposed in a predetermined position adjacent to the liquidcrystal light blocking section, and a light receiving member disposed onthe bottom of the open-ended cylindrical member for receiving anincident light.
 6. The welding-operation, liquid crystal, protectionmask of claim 1, wherein the liquid crystal member is a liquid crystalplate.
 7. The welding-operation, liquid crystal, protection mask ofclaim 1, wherein the liquid crystal driving power source is a solarbattery.
 8. The welding-operation, liquid crystal, protection mask ofclaim 1, wherein the cover plate is a transparent protection plate.